Cleaning and etching methods and their apparatuses

ABSTRACT

A cleaning method for removing fats, oils, and silicon small particles, which are conventionally difficult to remove, adhering to devices and carriers used to manufacture a semiconductor wafer or a semiconductor device. An etching method is also disclosed. XeF 2  gas produced by sublimation is made to contact with an object to be cleaned in a vacuum atmosphere so as to decompose and gasify the oils and fats and to remove silicon small particles by etching. Prior to the cleaning, when a trace amount of residual water is left in the vacuum atmosphere, H 2 O reacts with XeF 2 , and HF is produced. For example, a native oxide SiO 2  formed on the surface of silicon small particles can be removed, and XeF 2  directly reacts with silicon, therby enabling etching. The cleaning etching rates are extremely high.

TECHNICAL FIELD

[0001] The present invention relates to, in a semiconductor wafer orsemiconductor device manufacturing process, methods and apparatuses forremoving by cleaning dust from a silicon wafer, extremely minute siliconpieces that have become stuck in a carrier, or an oil film or the likecaused by oily components or the like that have leaked out from a pumpor the like of any of various manufacturing apparatuses installed in aclean room or sebum generated from workers, and more specificallyrelates to a dry cleaning method, an etching method, and apparatusestherefor that enable the removal of polymer, grease, metal, an nativeoxide on silicon and so on through a method using XeF₂ gas.

BACKGROUND ART

[0002] In the manufacture of semiconductor wafers and semiconductordevices, regarding manufacturing apparatuses therefor, to prevent theprocessed products being contaminated with various types of soiling,attach ed substances, and so on, or to carry out vapor depositionprocesses, hermetically sealed chambers are primarily used, and anapparatus constitution in which a plurality of such chambers arearranged connected together is widely used.

[0003] Moreover, in such manufacture, housing means called a wafercarrier is used for conveying wafers and transferring the wafers betweenapparatuses, or a handling apparatus or the like for holding the wafersone at a time is used. Such a wafer carrier has a constitution in whicha large number of semiconductor wafers are held in a line by means of alarge number of grooves provided in an inside surface of the wafercarrier, and minute silicon dust is liable to be generated.

[0004] Every time it is required to increase the degree of integrationof semiconductor devices, it is required to reduce the amount ofattached matter on semiconductor wafers, and hence there is an increasein the required degree of cleanliness in the various process apparatusesand so on. Consequently, minute silicon dust, and also oil films and soon caused by oily components or the like that have leaked out from apump or the like of any of various manufacturing apparatuses installedin a clean room or sebum generated from workers in the clean room, whichare difficult to remove, are the most loathed contaminants.

[0005] In the case of cleaning a series of device manufacturingapparatuses that have been set up using a cleaning liquid containing,for example, a surfactant for removing oily components and so on,another way of cleaning is required to remove the surfactant and so on,and hence contamination occurs in chain-like fashion; in general, acleaning liquid that does not contain a surfactant is thus used, andhence it is extremely difficult to remove the above-mentioned oil filmsand so on.

[0006] Moreover, as insertion of silicon wafers into and carrying out ofsilicon wafers from the various apparatuses is continuously carried out,it is impossible to avoid extremely minute silicon dust becomingattached inside the apparatuses; the surface of this dust is oxidizedover time, whereby a tough oxide film is produced.

[0007] Furthermore, wafer carriers of which the inside and outsidesurfaces have become soiled through repeated use are periodicallycleaned since this soiling will cause contamination of the semiconductorwafers themselves. Up until now the cleaning of wafer carriers has beencarried out through automatic cleaning using a high-pressure jet,Megasonic cleaner or the like, or hand brush cleaning using an organicsolvent. However, it has not been easy to remove extremely minutesilicon pieces that have become stuck in a carrier.

DISCLOSURE OF THE INVENTION

[0008] It is an object of the present invention to provide a cleaningmethod and an apparatus therefor which, in the case of any of variousapparatuses, a carrier or the like used in the manufacture ofsemiconductor wafers or semiconductor devices, are capable of removingminute silicon dust attached and accumulated inside the apparatuses, orremoving by cleaning minute silicon pieces and grease that areconventionally difficult to remove.

[0009] Moreover, it is an object of the present invention to provide anetching method and an apparatus therefor which, during the manufactureof semiconductor wafers and semiconductor devices, are capable ofremoving an oxide film on the surface of a silicon wafer and alsocontinuously etching the silicon.

[0010] Aiming for a method capable of removing by cleaning silicon dustand grease which is attached to an apparatus and is difficult to remove,minute silicon pieces and silicon oxide pieces that have become stuck ina carrier, and so on, for example capable of cleaning away suchsubstances even from the inside of an airtight chamber, the presentinventors carried out various studies into decomposed substances such asthe above-mentioned grease and the like, and as a result discovered thatif XeF₂ gas obtained by sublimation is made to come into contact withand act on an article to be cleaned in a vacuum atmosphere, then theabove-mentioned grease and the like can be decomposed and vaporized, andmoreover silicon pieces and the like can be removed by etching.

[0011] Moreover, the present inventors discovered that if theabove-mentioned vacuum atmosphere is made to contain a trace of water,then the H₂O and the XeF₂ in the atmosphere react with one another toproduce HF, and hence for example an native oxide on silicon formed onthe surface of silicon pieces or the like can be removed, and thensubsequently the silicon can be etched through the XeF₂ acting directlyon the silicon in an atmosphere not containing water; the series ofcleaning and etching reactions is extremely rapid, and hence cleaningand etching can be carried out in a reduced time.

[0012] Furthermore, the present inventors discovered that if the twosteps are carried out in succession, i.e. the amount of SiO₂ oxide filmformed on silicon pieces to be removed is estimated, a prescribed amountof water is made to remain behind in or is added to the atmosphere, andXeF₂ gas is supplied in, thus first removing the native oxide on siliconformed on the surface of the silicon pieces or the like, and then afterthe water has been consumed the XeF₂ gas is made to act directly on thesilicon pieces, thus removing the silicon itself by etching, then itbecomes possible to clean the inside of an apparatus for manufacturingso-called silicon wafers, semiconductor devices or the like; moreover,if for example a pre-existing device manufacturing apparatus is providedwith an XeF₂ gas supply apparatus and a dehumidification orhumidification apparatus, then completely dry cleaning of the apparatuscan be suitably carried out; the present invention was thusaccomplished.

[0013] That is, the present invention provides a cleaning method and anetching method, characterized by causing XeF₂ gas to come into contactwith and act on an article to be cleaned in a reduced-pressure or vacuumatmosphere containing a trace of water or having had a prescribed amountof water added thereto, and then causing XeF₂ gas to come into contactwith and act on the article to be cleaned in a vacuum atmosphere notcontaining water.

[0014] Moreover, the present inventors also propose a cleaning methodand an etching method characterized in that, in the above methods, thearticle to be cleaned (article to be processed) is a gas passageway orthe inside of any of various chambers of a semiconductor wafer or devicemanufacturing apparatus, or any of a semiconductor wafer, asemiconductor device, and a carrier thereof.

[0015] Furthermore, the present inventors also propose cleaning andetching apparatuses in which a publicly-known silicon wafer or devicemanufacturing apparatus is provided with XeF₂ gas supply means anddehumidification and/or humidification means.

[0016] The present invention provides a cleaning method in which XeF₂gas contacts and acts on an article to be cleaned in a reduced-pressureor vacuum atmosphere containing a required amount of water. Then, XeF₂gas contacts and acts on the article to be cleaned in a reduced-pressureor vacuum atmosphere not containing water.

[0017] According to an embodiment of the invention described above, theXeF₂ gas can be supplied continuously in the step using the atmospherecontaining water and the step using the atmosphere not containing water.

[0018] The present invention also provides a cleaning apparatusincluding a pressure-reducing/vacuum means; XeF₂ gas generating means;and means for making an atmosphere in the apparatus contain water,wherein XeF₂ gas contacts and acts on an article to be cleaned in areduced-pressure or vacuum atmosphere containing a required amount ofwater. Then, the XeF₂ gas contacts and acts on the article to be cleanedin a reduced-pressure or vacuum atmosphere not containing water.

[0019] Furthermore, the present invention provides an etching method inwhich XeF₂ gas contacts and acts on an article to be processed in areduced-pressure or vacuum atmosphere containing a required amount ofwater. Then, XeF₂ gas contacts and acts on the article to be processedin a reduced-pressure or vacuum atmosphere not containing water.

[0020] According to an embodiment of the invention described above, theXeF₂ gas can be supplied continuously in the step using the atmospherecontaining water and the step using the atmosphere not containing water.

[0021] The present invention also provides an etching apparatusincluding a pressure-reducing/vacuum means; XeF₂ gas generating means;and means for making an atmosphere in the apparatus contain water,wherein XeF₂ gas contacts and acts on an article to be processed in areduced-pressure or vacuum atmosphere containing a required amount ofwater. Then, the XeF₂ gas contacts and acts on the article to beprocessed in a reduced-pressure or vacuum atmosphere not containingwater.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is an explanatory drawing showing a constitution in whichan apparatus for continuously supplying XeF₂ gas is connected to achamber of a device manufacturing apparatus.

[0023]FIG. 2 is an explanatory drawing showing a carrier cleaningprocess.

BEST MODE FOR CARRYING OUT THE INVENTION

[0024] In the present invention, XeF₂ is used by making crystals thereofinto a gas at raised temperature or in a reduced-pressure or vacuumatmosphere; conventionally, XeF₂ gas is known as a gas for isotropicetching of silicon. The present inventors discovered that such XeF₂ gashas a function of decomposing and vaporizing grease, and the presentinvention utilizes this effectively.

[0025] Moreover, the present inventors discovered that if XeF₂ gas isreacted with a trace of residual water or added water in the atmosphereto produce HF gas, and for example an SiO₂ oxide film on a silicon waferis removed using the HF gas, and then etching of the silicon is carriedout using the XeF₂ gas, then the total processing time can be shortened;the present invention utilizes this effectively.

[0026] In the case of cleaning the inside of a gas passageway and/or theinside of any of various chambers of a semiconductor wafer or devicemanufacturing apparatus, a constitution is adopted such that it ispossible to introduce into the apparatus using a separate pre-existinggas passageway XeF₂ gas obtained by subliming XeF₂ crystals in, forexample, a low-pressure expansion chamber; the inside of the chamber orpassageway to be cleaned is, for example, evacuated, and setting iscarried out such that a trace of water remains behind, and then the XeF₂gas is introduced, whereby first HF gas is produced, and hence an oxidefilm on silicon dust attached to the inside of the chamber or passagewayto be cleaned is removed; then, after the water has run out, the silicondust itself and grease attached to the inside of the chamber orpassageway to be cleaned are decomposed and vaporized by the suppliedXeF₂ gas, and after that evacuation is carried out, thus completingexhaustion of the XeF₂ gas; cleaning of the inside of the chamber orpassageway can thus be achieved.

[0027] In the case of cleaning a carrier, by adding an XeF₂ processingstep that also combines drying to a conventional carrier cleaningprocess, it becomes possible to remove an native oxide on silicon onextremely minute silicon pieces that could not be removedconventionally, and then remove the silicon pieces themselves and an oilfilm.

[0028] For example, the inside of a dry processing chamber housing thecarrier is evacuated, XeF₂ gas is introduced in from an XeF₂ gas supplyunit, and is thus made to come into contact with and act on the carrierand hence decompose and vaporize grease attached to the carrier, andmoreover etching of silicon pieces attached to the carrier is carriedout. When blowing on the gas in this processing process, only the XeF₂gas is blown on.

[0029] During the above-mentioned evacuation, a trace of residual wateris left behind, whereby the H₂O and the XeF₂ react with one another toproduce HF, and hence the native oxide on the silicon pieces is removedin advance; the etching by the XeF₂ gas thus becomes more effective.

[0030] Subsequently, evacuation is carried out, thus completingexhaustion of the XeF₂ gas, and then the pressure inside the chamber isadjusted, thus completing the cleaning of the carrier; a cleaning effectbetter than with a conventional cleaning technique can be obtained.

[0031] As the XeF₂ gas supply unit in the present invention, anexpansion chamber constituted as indicated in the examples is preferablyused. That is, XeF₂ gas is obtained by subliming XeF₂ crystals in alow-pressure expansion chamber, and a constant amount of the XeF₂ gas ismaintained, or every time the XeF₂ gas is generated the XeF₂ gas issupplied elsewhere due to the XeF₂ processing, whereby the pressureinside the expansion chamber drops, and hence the crystals naturallystart to sublime again; it thus becomes possible to supply the XeF₂ gascontinuously.

[0032] Moreover, a conventional publicly-known pulse process in whichgas supply and exhaustion are carried out alternately can also be usedwith the present invention, although there is a problem of theprocessing time becoming long.

[0033] As the means for leaving behind the required amount of water inor supplying the required amount of water into the gas passageway orchamber, for example vacuum-producing means such as a publicly-knownvacuum pump can be used together with any of various publicly-knowndehumidification means and/or humidification means; it is also possibleto add separately generated water vapor using an ordinary gas flowcontroller. Furthermore, cooling means is also effective, for example inthe case of carrying out etching of a silicon wafer, it is possible tocool the silicon wafer at the same time as producing the vacuum, thusuniformly attaching and freezing water onto the wafer surface, and hencemaking water remain behind, or it is possible to make water remainbehind in required places. Here, regarding the required amount of watermade to remain behind or added using any of the various means, in thecase that gas is continuously supplied using the above-mentioned XeF₂gas supply unit, after the water has been consumed in the chamber or thelike, a step involving XeF₂ gas alone is switched over to.

[0034] When etching a silicon wafer according to the present invention,to remove an oxide film formed on the surface thereof, a trace ofresidual water in the atmosphere is utilized or a prescribed amount ofwater added to the atmosphere is reacted with the XeF₂ gas to produce HFgas; however, the rate of etching by the HF gas is different for anative oxide and a thermal oxide film, and hence for example theconcentration of the HF gas itself can be changed, and thus whencarrying out the etching various conditions such as the amounts of theXeF₂ gas and the water can be selected as appropriate.

EXAMPLES Example 1

[0035] An XeF₂ gas continuous supply apparatus was connected to achamber of a publicly-known device manufacturing apparatus as shown inFIG. 1. Specifically, the continuous supply apparatus was constituted byconnecting an XeF₂ crystal cartridge 1 to an expansion chamber 2, andthen connecting via a flow controller 3 to a pre-existing gas supplypipe leading to a process chamber 4.

[0036] In addition to a process gas supply pipe, not shown in thedrawing, a vacuum pump apparatus 5 was connected to the process chamber4, whereby the atmosphere in the chamber 4 could be controlled asdesired. Consequently, it becomes possible to accurately control theflow rate of the XeF₂ gas introduced into the process chamber 4, andmoreover it becomes possible to control the gas flow rate and theprocess chamber 4 pressure independently of one another.

[0037] The inside of the process chamber 4 is evacuated from an airatmosphere to a vacuum, with a required amount of residual water beingleft behind (method 1), or else water vapor is added via a flowcontroller 7 from an H₂O gas supply apparatus 6 using a separate gaspipeline as shown in the drawing, whereby the amount of water in theatmosphere in the chamber 4 is controlled in advance to be a prescribedamount (method 2). Here, both of these methods (method 1, method 2) wereimplemented, changing over the chamber.

[0038] Next, XeF₂ crystals are sublimed in the expansion chamber 2 at apressure below the sublimation point to obtain XeF₂ gas, and once thepressure of the XeF₂ reaches the sublimation point (a few Torr), theXeF₂ gas is introduced into the process chamber 4.

[0039] Moreover, a method 3 in which the water vapor is added via theflow controller 7 from the H₂O gas supply apparatus 6 at the same timeas introducing the XeF₂ into the process chamber 4 was also implemented.

[0040] Here, at an initial stage of gas introduction when water isalready present in the process chamber 4 (method 1, method 2), or whenwater is introduced at the same time as the XeF₂ (method 3), the XeF₂reacts with the water to produce HF; a thermal oxide film or the like onthe surface of silicon dust attached to an exhaust system and in thechamber 4 was thus removed by cleaning.

[0041] After that, as the XeF₂ is supplied and hence the pressure insidethe expansion chamber drops, the crystals naturally start to sublimeagain, and hence the XeF₂ gas is supplied continuously; once the waterin the process chamber 4 runs out, or the addition of the water vaporfrom the flow controller 7 is stopped, the generation of HF ceases, andthus cleaning by the XeF₂ gas is then carried out; metal, insulatingmaterial and polymer attached to the exhaust system and in the chamber 4could thus be removed by cleaning.

[0042] In FIG. 1, a constitution is shown in which the XeF₂ gas supplysystem is connected directly to the process chamber 4; however, when anapparatus was manufactured having a constitution in which the XeF₂ gassupply system, or this and also the water vapor supply system areconnected to gas piping, not shown in the drawing, for supplying theprocess gas to the process chamber 4, and methods 1 to 3 described abovewere implemented, it was possible to remove by cleaning silicon dust,polymer and so on that was attached in large amounts inside the processgas piping leading to the chamber 4 and in the vicinity of a connectingpart between this piping and the chamber 4.

Example 2

[0043] Using a process chamber having an XeF₂ gas continuous supplyapparatus as used in Example 1, etching of monocrystalline siliconwafers for devices was carried out. Note that, although not shown in thedrawing, in the example of the apparatus in FIG. 1, the XeF₂ gas supplyport was disposed close to a stage on which the silicon wafer wasplaced, and a constitution preferable for an etching apparatus wasadopted such that the XeF₂ gas would flow uniformly over the wafersurface.

[0044] Here, 3 μm-deep pattern formation with 100 mm spacing was carriedout on a 4-inch wafer. The XeF₂ etching process conditions were XeF₂gas, 15 sccm, and a pressure of 20 Pa (150 mTorr).

[0045] Evacuation was carried out to create a prescribed atmosphere, andbefore commencing the etching, H₂O was added for 5 seconds at a flowrate of 50 sccm from a separate gas introduction port without carryingout exhaustion, thus introducing water vapor into the process chamber.Then, the XeF₂ gas was introduced in continuously while carrying outexhaustion, thus carrying out the etching.

[0046] Moreover, for comparison, when carrying out the above etchingprocess, the etching was carried out by continuously introducing XeF₂gas, without introducing water vapor before commencing the etching.

[0047] In the case of the etching process of the present invention inwhich water vapor was introduced before commencing the etching, thetotal process time was 15 minutes. Moreover, in the case of the etchingprocess in which water vapor was not introduced for comparison, thetotal process time was 18 minutes.

[0048] A 5 Å- to 10 Å-thick native oxide was formed on the siliconwafer, but in the case of the etching process of the present invention,it is thought that because water vapor was introduced before commencingthe etching and hence HF was generated through reaction with the XeF₂,the native oxide on the wafer surface was removed almostinstantaneously, and thus the etching by the XeF₂ gas was carried outwithout delay, and hence the etching was carried out at the naturaletching rate of silicon by XeF₂ gas, i.e. 0.2 μm/min.

[0049] However, in the case of the etching process of the comparativeexample, the XeF₂ gas first etches the native oxide, but the etchingrate of an SiO₂ film by XeF₂ gas is extremely slow; a large differencein the total process time thus arose.

Example 3

[0050] As shown in FIG. 2, a wafer carrier automatic cleaning apparatusaccording to the present invention has a constitution in which a loader10, a brush cleaning apparatus 20, an ultrasonic cleaning apparatus 30,a finishing cleaning apparatus 40, a dry cleaning apparatus 50, and anunloader 60 are arranged in tandem.

[0051] A wafer carrier to be cleaned is conveyed into the cleaningapparatuses by the loader 10. The wafer carrier that has been conveyedin is then carried to the brush cleaning apparatus 20 by a robot. Thebrush cleaning apparatus 20 has a cleaning bath and a cleaning robotattached thereto. A cleaning liquid comprising, for example, a mixtureof pure water and a neutral detergent is introduced in from a bottompart of the cleaning bath and overflows, whereby the liquid level iskept constant. The constitution is such that a rotating table isprovided in the bottom part of the cleaning bath, and the carrier to becleaned is supported in the bath in a state immersed in the cleaningliquid with an opening part thereof facing upward, and is rotated. Thecleaning robot has rotating brushes, and brushes inside and outsidesurfaces of the carrier.

[0052] Once the brush cleaning of the carrier has been completed, thecarrier is conveyed to the ultrasonic cleaning apparatus 30 by therobot. The ultrasonic cleaning apparatus 30 is able to clean the carrierusing ultrasound generated in warm pure water that has been heated to 40to 60° C. Once the ultrasonic cleaning has been completed, the carrieris conveyed to the finishing cleaning apparatus 40; the finishingcleaning apparatus 40 holds pure water that is continuously supplied ina laminar flow state from a bottom part of a cleaning bath of thefinishing cleaning apparatus 40 and overflows, and the carrier isimmersed in this pure water, and is thus subjected to finishingcleaning. Through the ultrasonic cleaning and the finishing cleaning,minute pieces of foreign matter and soiling remaining on the surfaces ofthe carrier are removed.

[0053] An XeF₂ gas continuous supply apparatus 70 as used in Example 1is connected to the dry cleaning apparatus 50. In the dry cleaningapparatus 50, first the carrier is rotated at approximately 1,000 rpmand thus spin-dried. Next, the inside of the chamber is evacuated (30 to60 sec), whereby the pressure is reduced and water is removed from thesurfaces of the carrier. Furthermore, under a 133.3 Pa to 266.3 Pa (1Torr to 2 Torr) atmosphere, XeF₂ gas is introduced in from the XeF₂ gassupply apparatus, whereby cleaning processing is carried out (60 sec).

[0054] First, the introduced XeF₂ gas reacts with residual water in thechamber to produce HF, and thus an oxide film on the surface ofextremely minute silicon pieces that have become stuck in the carriersurfaces is removed by cleaning. Then, the supplied XeF₂ acts directlyon the carrier; the minute silicon pieces and also attached metal,insulating material, polymer and so on could thus be removed bycleaning.

[0055] After that, evacuation is carried out (30 to 60 sec), thusexhausting the XeF₂. Then, N₂ is vented (20 to 30 sec) to adjust thepressure inside the chamber, and then the carrier is taken out from thedry cleaning apparatus 50 by another robot, and carried to the unloader60 and stored.

[0056] In the dry cleaning apparatus 50, metal, insulating material,polymer and so on, and also extremely minute silicon pieces that havebecome stuck in the carrier surfaces, which could not be removed byconventional brush cleaning, could be removed.

INDUSTRIAL APPLICABILITY

[0057] With the present invention, using HF generated from XeF₂ gas anda prescribed amount of water in the atmosphere that has been controlledby being left behind or added, it is possible to remove a silicon oxidefilm on the surface of minute silicon dust attached to a gas passagewayor the inside of any of various chambers of a semiconductor wafer orsemiconductor device manufacturing apparatus, or any of a semiconductorwafer, a semiconductor device, and a carrier thereof; subsequently,using the XeF₂ gas, it is possible to remove the silicon dust itself,and selectively etch polymer, grease, metal and so on, which have beendifficult to remove conventionally; it thus becomes possible to cleanthe inside of any of the above apparatuses in a relatively short timeand by a dry cleaning method.

[0058] With the present invention, by providing a pre-existingsemiconductor wafer or semiconductor device manufacturing apparatus withan XeF₂ gas continuous supply apparatus and means for making theatmosphere contain water such as a dehumidification or humidificationapparatus, completely dry cleaning of the apparatus can be suitablycarried out.

[0059] In particular, in the manufacture of semiconductor wafers andsemiconductor devices these days, an extremely high degree ofcleanliness is required for the atmosphere in the apparatus; however,with the present invention, there is an advantage that this can be copedwith, since extremely minute silicon dust, polymer and the like, whichhave been difficult to remove conventionally, can be removed throughcompletely dry cleaning.

[0060] Moreover, with the present invention, by using a method in whichthe XeF₂ gas is supplied continuously, it is possible to remove an SiO₂oxide film such as a native oxide formed on a silicon wafer using HF gasgenerated from the XeF₂ gas and water in the atmosphere, and then etchthe silicon using the XeF₂ gas; the total processing time of the etchingprocess can thus be shortened.

1. A cleaning method comprising a step of causing XeF₂ gas to come intocontact with and act on an article to be cleaned in a reduced-pressureor vacuum atmosphere containing a required amount of water, and then astep of causing XeF₂ gas to come into contact with and act on thearticle to be cleaned in a reduced-pressure or vacuum atmosphere notcontaining water.
 2. The cleaning method according to claim 1, whereinthe XeF₂ gas is supplied continuously in both the step using theatmosphere containing water and the step using the atmosphere notcontaining water.
 3. The cleaning method according to claim 1, whereinthe article to be cleaned is a gas passageway or the inside of any ofvarious chambers of a semiconductor wafer manufacturing apparatus or asemiconductor device manufacturing apparatus.
 4. The cleaning methodaccording to claim 1, wherein the article to be cleaned is any of asemiconductor wafer, a semiconductor device, and a carrier thereof.
 5. Acleaning apparatus, in which a semiconductor wafer manufacturingapparatus or a semiconductor device manufacturing apparatus havingpressure-reducing/vacuum means is provided with XeF₂ gas generatingmeans and means for making the atmosphere in the apparatus containwater, and which carries out a step of causing XeF₂ gas to come intocontact with and act on an article to be cleaned in a reduced-pressureor vacuum atmosphere containing a required amount of water, and then astep of causing XeF₂ gas to come into contact with and act on thearticle to be cleaned in a reduced-pressure or vacuum atmosphere notcontaining water.
 6. An etching method comprising a step of causing XeF₂gas to come into contact with and act on an article to be processed in areduced-pressure or vacuum atmosphere containing a required amount ofwater, and then a step of causing XeF₂ gas to come into contact with andact on the article to be processed in a reduced-pressure or vacuumatmosphere not containing water.
 7. The etching method according toclaim 6, wherein the XeF₂ gas is supplied continuously in both the stepwith the atmosphere containing water and the step with the atmospherenot containing water.
 8. The etching method according to claim 6,wherein the article to be processed is a silicon wafer.
 9. An etchingapparatus, in which a semiconductor wafer manufacturing apparatus or asemiconductor device manufacturing apparatus havingpressure-reducing/vacuum means is provided with XeF₂ gas generatingmeans and means for making the atmosphere in the apparatus containwater, and which carries out a step of causing XeF₂ gas to come intocontact with and act on an article to be processed in a reduced-pressureor vacuum atmosphere containing a required amount of water, and then astep of causing XeF₂ gas to come into contact with and act on thearticle to be processed in a reduced-pressure or vacuum atmosphere notcontaining water.
 16. (New): The cleaning apparatus according to claim9, further comprising a gas flow controller for supplying water vaporinto the atmosphere containing water in the apparatus.
 17. (New): Thecleaning apparatus according to claim 9, further comprising at least oneof a dehumidification means and a humidification means for controllingthe amount of the water in the atmosphere containing water in theapparatus.